1. Field of the Invention
The present invention relates first of all to a method for transmitting a digital data stream D.sub.i, arriving at a first rate, by means of a digital channel having a second rate higher than said first rate, wherein, on emission, the digital stream D.sub.i is chopped into packets of p bits, a preamble comprising at least one synchronization word is associated with each packet and the packets are transmitted over the channel.
The present invention relates then to the transmission of digital information by means of a higher rate channel, the channel having a priori no phase relation with the primary digital channel.
Such problems arise in particular in transmission techniques using short wave links, digital optical cables, or any digital information transmission medium.
2. Description of the Prior Art
A method of the above defined type is already known, described in the article by W. E. Baker et al: "A buffer store for data transmission" BELL TELEPHONE SYSTEM, Technical Publications, Monograph 4139, May 1962, pp 1-5, New York, USA. However, since this method does not provide for recovery of the initial clock signal associated with the digital stream D.sub.i, it seems especially adapted to transmission of a synchronous type digital information, that is to say groups of bits separated by dead periods, each group of bits forming for example a character.
The present invention aims at overcoming this drawback by providing a method which, by providing recovery of the initial clock signal, can be very well applied to the transmission of continuous synchronous type digital streams, for which recovery of the clock signal is indispensable.